Quench tests at the Large Hadron Collider with collimation losses at 3.5 Z TeV

Abstract

The Large Hadron Collider (LHC) has been operating since 2010 at 3.5 TeV and 4.0 TeV without experiencing quenches induced by losses from circulating beams. This

situation might change at 7 TeV where the quench margins in the super-conducting magnets are reduced. The

critical locations are the dispersion suppressors (DSs) at either side of the cleaning and experimental insertions, where

dispersive losses are maximum. It is therefore crucial to understand the quench limits with beam loss distributions

alike those occurring in standard operation. In order to address this aspect, quench tests were performed by inducing

large beam losses on the primary collimators of the betatron cleaning insertion, for proton and lead ion beams of 3.5 Z TeV, to probe the quench limits of the DS magnets. Losses

up to 500 kW were achieved without quenches. The measurement technique and the results obtained are presented,

with observations of heat loads in the cryogenics system.